| Popis: |
We report a new measurement of the cross-section ς(e+e-→Υ(nS)ϖ+ϖ-) (n = 1,2,3) in the region √s = 10.63 GeV/c2 to 11.02 GeV/c2, including sixteen 1 fb-1 scan points not previously reported on, six previously reported scan points, and 121 fb-1 at the Υ(5S) resonance, all taken with the Belle detector at KEK in Tsukuba, Japan. The shape is compared with that of ςb=ς(e+e- → bb → hadrons), measured using the sixteen 1 fb-1 scan points and sixty-one 50 pb-1 scan points. This analysis supersedes the previous measurement with additional scan and Υ(5S) data, by fitting both cross-sections using the same model, and by introducing a model-insensitive correction for the Υ(nS)ϖ+ϖ- acceptance. We measure the mass and width of the Υ(5S), M5S=10884.4±1.4±1.6 MeV and Γ5S=50±5±l3 MeV, consistent with the measurements obtained from a concurrent Rb analysis. |
